Research on the Shear Performance of T-PBL Connectors at the Wind Turbine Tower-Foundation Interface

With the development of wind turbines toward large capacities and higher loads， the mechanical properties of the tower-foundation interface have become increasingly critical. To enhance the composite action and anchorage performance of the interface， this study proposes a novel T-PBL connector. The connector is developed by adding flange plates at the ends of traditional PBL connectors and adopting a staggered hole arrangement， aiming to improve the stress distribution between holes， increase compressive and shear capacities， and enhance the confinement effect on the concrete. Eight push-out tests on T-PBL connectors were designed and conducted to investigate their shear performance， with the transverse hole spacing and flange width being selected as the main research parameters. The failure modes， load-slip responses， shear bearing capacity， shear stiffness， and ductility were systematically analyzed， and a shear capacity calculation method for T-PBL connectors was proposed. The results revealed that the failure mode of the T-PBL connectors was primarily characterized by cracking of the concrete slab and local crushing of the concrete around the holes， while noticeable local plastic deformation occurred in both the steel plate holes and the penetrating bars. The T-PBL connectors exhibited excellent shear bearing capacity， shear stiffness， and ductility. When the transverse hole spacing increased from 0 to 80 mm， the shear bearing capacity increased by approximately 26.1%， while the shear stiffness decreased by about 12.9%. With the increase in flange width， both shear bearing capacity and stiffness exhibited a trend of first increasing and then decreasing. Based on the experimental results， a shear bearing capacity calculation formula considering the effects of flange width and hole spacing was proposed. The calculated values showed good agreement with the test results.